#bg{

position:fixed;

top:0;
left:0;

width:100%;
height:100%;

z-index:-100;

background:
radial-gradient(circle at center,#090b1f,#050816 80%);

}
body{

background:

radial-gradient(circle at top,#13184b 0%,#050816 60%,#02030a 100%);

}